Trend of Change in the Duration of Jet Streams over Iraq for the Period 1980-2024

Abstract

This research studies the jet streams over Iraq (the subpolar jet stream and the subtropical jet stream) by analyzing weather maps at the 300 and 200 millibar levels and the nighttime observation (0z) for the periods (1980-1991), (1991-2002), (2002-2013), and (2013-2024) during the months from October to May, which are the rainy months in Iraq. The study calculates the amount of change to determine the trend of change, whether positive (increasing) or negative (decreasing). The results showed a decreasing trend for the subpolar jet stream and an increasing trend for the subtropical jet stream across all study regions and months. The highest duration of the subpolar jet stream was recorded in the northern region in January, with 20.5 days, while the highest duration of the subtropical jet stream was recorded in the southern region in May, with 12.4 days.